Re: [HACKERS] write past chunk end in ExprContext / to_char
Tom Lane wrote: > Patrick Welche <[EMAIL PROTECTED]> writes: > > With today's CVS code (originally noticed with 8.2beta3), on a PC where > > INT_MAX=0x7FFF=2147483647 > > > postgres=# select to_char(2147483648,'999,999,999'); > > WARNING: detected write past chunk end in ExprContext 0x845509c > > WARNING: detected write past chunk end in ExprContext 0x845509c > > Yech ... it's scribbling on the output of int8out, which is bad enough, > but it's assuming that buffer will be long enough when it demonstrably > isn't. > > Some days I think we ought to throw out formatting.c and rewrite it from > scratch; it's probably the most poorly-coded module in all of Postgres. Agreed from personal experience. I am in there wacking it around it seems every release. -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---(end of broadcast)--- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
Re: [HACKERS] write past chunk end in ExprContext / to_char
imad <[EMAIL PROTECTED]> writes:
> This is the problematic part in formatting.c, function "dch_time".
> intsiz = strlen(tmtcTzn(tmtc));
>
> if (arg == DCH_TZ)
> strcpy(inout, tmtcTzn(tmtc));
> else
> {
> char *p = palloc(siz);
>
> strcpy(p, tmtcTzn(tmtc));
> strcpy(inout, str_tolower(p));
> pfree(p);
> }
> return siz;
Hmm. That was not the buffer overrun I was looking at, but it sure
looks like another one :-(. Thanks for spotting it!
regards, tom lane
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Re: [HACKERS] write past chunk end in ExprContext / to_char
This is the problematic part in formatting.c, function "dch_time".
int siz =
strlen(tmtcTzn(tmtc));
if (arg == DCH_TZ)
strcpy(inout, tmtcTzn(tmtc));
else
{
char *p = palloc(siz);
strcpy(p, tmtcTzn(tmtc));
strcpy(inout, str_tolower(p));
pfree(p);
}
return siz;
here, doing a palloc with "siz+1" solves the issue but following /
making the convention, pstrdup should be used instead which is
specifically written for this purpose.
Probably too small a change for a patch ?
--Imad
www.EnterpriseDB.com
On 6/29/07, Tom Lane <[EMAIL PROTECTED]> wrote:
Patrick Welche <[EMAIL PROTECTED]> writes:
> With today's CVS code (originally noticed with 8.2beta3), on a PC where
> INT_MAX=0x7FFF=2147483647
> postgres=# select to_char(2147483648,'999,999,999');
> WARNING: detected write past chunk end in ExprContext 0x845509c
> WARNING: detected write past chunk end in ExprContext 0x845509c
Yech ... it's scribbling on the output of int8out, which is bad enough,
but it's assuming that buffer will be long enough when it demonstrably
isn't.
Some days I think we ought to throw out formatting.c and rewrite it from
scratch; it's probably the most poorly-coded module in all of Postgres.
regards, tom lane
---(end of broadcast)---
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
---(end of broadcast)---
TIP 7: You can help support the PostgreSQL project by donating at
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Re: [HACKERS] write past chunk end in ExprContext / to_char
Patrick Welche <[EMAIL PROTECTED]> writes: > With today's CVS code (originally noticed with 8.2beta3), on a PC where > INT_MAX=0x7FFF=2147483647 > postgres=# select to_char(2147483648,'999,999,999'); > WARNING: detected write past chunk end in ExprContext 0x845509c > WARNING: detected write past chunk end in ExprContext 0x845509c Yech ... it's scribbling on the output of int8out, which is bad enough, but it's assuming that buffer will be long enough when it demonstrably isn't. Some days I think we ought to throw out formatting.c and rewrite it from scratch; it's probably the most poorly-coded module in all of Postgres. regards, tom lane ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [HACKERS] write past chunk end in ExprContext / to_char
Patrick Welche wrote: > With today's CVS code (originally noticed with 8.2beta3), on a PC where > INT_MAX=0x7FFF=2147483647 > > postgres=# select to_char(1234567890123,'999,999,999,999'); > WARNING: detected write past chunk end in ExprContext 0x845509c > WARNING: detected write past chunk end in ExprContext 0x845509c > to_char > -- > ###,###,###,### > (1 row) Yes, it fails in 7.3, 7.4, 8.0, 8.1, 8.2 and HEAD. Thanks for the report. -- Alvaro Herrera http://www.amazon.com/gp/registry/5ZYLFMCVHXC "Executive Executive Summary: The [Windows] Vista Content Protection specification could very well constitute the longest suicide note in history." Peter Guttman, http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
